1. Click the Windows icon> Settings icon and select the system.
2. Click "Power and Sleep> Additional power settings> Select Choose what closing the lid does".
3.When I close the lid: select “Do nothing”.
4. Press the F3 key in the hot key mode to set the projection mode to "second screen only". At this point, you can operate the computer with external monitor, external mouse, external keyboard and other devices when closing the computer.
